NOTE:
Please don't use the plain text here as a patch because it most probably 
is corrupted by my webmail client.
Attached is a copy of the following text guaranteed to have correct 
tabs/spaces.
-------------------------

Before this patch the max3421-hcd driver could only use
statically linked platform data to initialize its parameters.
This prevented it from being used on systems using device
tree.

The data taken from the device tree is put into dev->platform_data
when CONFIG_OF is enabled and the device is an OpenFirmware node.

The driver's 'compatible' string is 'maxim,max3421'

Binding documentation is also added with this patch.

Signed-off-by: Alexander Amelkin <alexander@amelkin.msk.ru>
---
  .../devicetree/bindings/usb/maxim,max3421-hcd.txt  | 19 +++++
  drivers/usb/host/max3421-hcd.c                     | 96 
++++++++++++++++++++--
  2 files changed, 110 insertions(+), 5 deletions(-)
  create mode 100644 
Documentation/devicetree/bindings/usb/maxim,max3421-hcd.txt

diff --git a/Documentation/devicetree/bindings/usb/maxim,max3421-hcd.txt 
b/Documentation/devicetree/bindings/usb/maxim,max3421-hcd.txt
new file mode 100644
index 0000000..a8b9faa
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/maxim,max3421-hcd.txt
@@ -0,0 +1,19 @@
+* SPI-based USB host controller Maxim Integrated max3421e
+
+Required properties:
+- compatible: must be "maxim,max3421"
+- reg: chip select number to which the max3421 chip is connected
+  (depends on master SPI controller)
+- spi-max-frequency: the operational frequency, must not exceed 
<26000000>
+- interrupt-parent: phandle of the associated GPIO controller to which 
the INT line
+  of max3421e chip is connected
+- interrupts: specification of the GPIO pin (in terms of the 
`interrupt-parent`)
+  to which INT line of max3421e chip is connected.
+  The driver configures MAX3421E for active low level triggered 
interrupts.
+  Configure your 'interrupt-parent' gpio controller accordingly.
+- vbus: <GPOUTx ACTIVE_LEVEL>
+  GPOUTx is the number (1-8) of GPOUT pin of max3421e used to drive 
Vbus.
+  ACTIVE_LEVEL is 1 or 0.
+
+Don't forget to add pinctrl properties if you need some GPIO pins 
reconfigured
+for use as INT. See binding information for the pinctrl nodes.
diff --git a/drivers/usb/host/max3421-hcd.c 
b/drivers/usb/host/max3421-hcd.c
index 369869a..f600052 100644
--- a/drivers/usb/host/max3421-hcd.c
+++ b/drivers/usb/host/max3421-hcd.c
@@ -61,6 +61,12 @@
  #include <linux/usb.h>
  #include <linux/usb/hcd.h>

+#if defined(CONFIG_OF)
+#include <linux/of_device.h>
+
+#define MAX3421_GPOUT_COUNT 8
+#endif
+
  #include <linux/platform_data/max3421-hcd.h>

  #define DRIVER_DESC    "MAX3421 USB Host-Controller Driver"
@@ -1699,6 +1705,10 @@ max3421_hub_control(struct usb_hcd *hcd, u16 
type_req, u16 value, u16 index,
     spin_lock_irqsave(&max3421_hcd->lock, flags);

     pdata = spi->dev.platform_data;
+   if (!pdata) {
+       dev_err(&spi->dev, "Device platform data is missing\n");
+       return -EFAULT;
+   }

     switch (type_req) {
     case ClearHubFeature:
@@ -1831,20 +1841,80 @@ static struct hc_driver max3421_hcd_desc = {
     .bus_resume =       max3421_bus_resume,
  };

+#if defined(CONFIG_OF)
+static struct max3421_hcd_platform_data max3421_data;
+
+static const struct of_device_id max3421_dt_ids[] = {
+   { .compatible = "maxim,max3421", .data = &max3421_data, },
+   { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, max3421_dt_ids);
+#endif
+
  static int
  max3421_probe(struct spi_device *spi)
  {
     struct max3421_hcd *max3421_hcd;
     struct usb_hcd *hcd = NULL;
     int retval = -ENOMEM;
+#if defined(CONFIG_OF)
+   struct max3421_hcd_platform_data *pdata = NULL;
+#endif

     if (spi_setup(spi) < 0) {
         dev_err(&spi->dev, "Unable to setup SPI bus");
         return -EFAULT;
     }

-   hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev,
-                dev_name(&spi->dev));
+   if (!spi->irq) {
+       dev_err(&spi->dev, "Failed to get SPI IRQ for node '%s'\n", 
spi->dev.of_node->full_name);
+       return -EFAULT;
+   }
+
+#if defined(CONFIG_OF)
+   if (spi->dev.of_node) {
+       /* A temporary alias structure */
+       union {
+           uint32_t value[2];
+           struct {
+               uint32_t gpout;
+               uint32_t active_level;
+           };
+       } vbus;
+
+       if(!(pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), 
GFP_KERNEL))) {
+           dev_err(&spi->dev, "failed to allocate memory for private 
data\n");
+           retval = -ENOMEM;
+           goto error;
+       }
+       spi->dev.platform_data = pdata;
+
+       if ((retval = of_property_read_u32_array(spi->dev.of_node, 
"vbus", vbus.value, 2))) {
+           dev_err(&spi->dev, "device tree node property 'vbus' is 
missing\n");
+           goto error;
+       }
+       pdata->vbus_gpout = vbus.gpout;
+       pdata->vbus_active_level = vbus.active_level;
+   }
+   else
+#endif
+   pdata = spi->dev.platform_data;
+   if (!pdata) {
+       dev_err(&spi->dev, "driver configuration data is not 
provided\n");
+       retval = -EFAULT;
+       goto error;
+   }
+   if (pdata->vbus_active_level > 1) {
+       dev_err(&spi->dev, "vbus active level value %d is out of range 
(0/1)\n", pdata->vbus_active_level);
+       retval = -EINVAL;
+       goto error;
+   }
+   if (pdata->vbus_gpout < 1 || pdata->vbus_gpout > 
MAX3421_GPOUT_COUNT) {
+       dev_err(&spi->dev, "vbus gpout value %d is out of range 
(1..8)\n", pdata->vbus_gpout);
+       retval = -EINVAL;
+       goto error;
+   }
+   hcd = usb_create_hcd(&max3421_hcd_desc, &spi->dev, 
dev_name(&spi->dev));
     if (!hcd) {
         dev_err(&spi->dev, "failed to create HCD structure\n");
         goto error;
@@ -1892,6 +1962,12 @@ max3421_probe(struct spi_device *spi)
             kthread_stop(max3421_hcd->spi_thread);
         usb_put_hcd(hcd);
     }
+#if defined(CONFIG_OF)
+   if (pdata && spi->dev.platform_data == pdata) {
+       devm_kfree(&spi->dev, pdata);
+       spi->dev.platform_data = NULL;
+   }
+#endif
     return retval;
  }

@@ -1908,14 +1984,12 @@ max3421_remove(struct spi_device *spi)
         if (hcd->self.controller == &spi->dev)
             break;
     }
+
     if (!max3421_hcd) {
         dev_err(&spi->dev, "no MAX3421 HCD found for SPI device %p\n",
             spi);
         return -ENODEV;
     }
-
-   usb_remove_hcd(hcd);
-
     spin_lock_irqsave(&max3421_hcd->lock, flags);

     kthread_stop(max3421_hcd->spi_thread);
@@ -1923,8 +1997,19 @@ max3421_remove(struct spi_device *spi)

     spin_unlock_irqrestore(&max3421_hcd->lock, flags);

+#if defined(CONFIG_OF)
+   if (spi->dev.platform_data) {
+       dev_dbg(&spi->dev, "Freeing platform data structure\n");
+       devm_kfree(&spi->dev, spi->dev.platform_data);
+       spi->dev.platform_data = NULL;
+   }
+#endif
+
     free_irq(spi->irq, hcd);

+   usb_remove_hcd(hcd);
+
+
     usb_put_hcd(hcd);
     return 0;
  }
@@ -1934,6 +2019,7 @@ static struct spi_driver max3421_driver = {
     .remove     = max3421_remove,
     .driver     = {
         .name   = "max3421-hcd",
+       .of_match_table = of_match_ptr(max3421_dt_ids),
     },
  };

--
2.7.4